1 clove garlic, peeled and smashed
1 28 oz can of San Marzano tomatoes
Put the onion, jalapeno, garlic and sugar in a blender or food processor and process until minced. Then add the can of tomatoes and process for at least a minute, until the mixture is completely smooth. Add the vinegar and water and pulse to combine. Transfer the mixture to a heavy bottomed pot and bring to a boil. Turn down the heat to a simmer. Add in the following:
a pinch of celery seed
I know that seems a little excessive, but these old sauces were real concoctions. Simmer the sauce, uncovered, for about an hour to an hour and a quarter. You don't have to hover over it, just stir occasionally. But like all good tomato sauces, it does have a tendency to splatter, so I used a splatter screen. When the sauce is thick enough for you, taste to check the seasonings, and pour it into clean jars. Let it cool before refrigerating. It should keep at least a month in the fridge.